Apparatus for coating



Sept. 30, 1941. c. D. KNOWLTON 2,257,261

APPARATUS FOR COATING Filed Nov. 24, 1939 3 Sheets-Sheet 1 P 1941- c. D. KNOWLTVON 2,257,261

APPARATUS FOR COATING Filed Nov. 24, 1939 3 Sheets-Sheet 2 P 1941- c. D. KNOWLTON 2,257,261

APPARATUS FOR COATING Filed Nov. 24, 1939 5 Sheets-Sheet 3 Fig.7.

Patented Sept. 30, 1941 2,257,261 APPARATUS FOR COATING Cutler D. Knowlton, Beverly, Masa, assignor, by

mesne assignments, to Hoague-Sprague Corporation, Lynn, Mass., a corporation of Massachusetts Application November 24, 1939, Serial No. 305,945

9 Claims form thickness of coating material to an object u to be coated. A conventional type of machine for applying coating to articles employs a coating supply or pick-up roll which receives coating from a reservoir, the coating being supplied thereby to an applying roll rotating in contact with the supply roll, the material to be coated passing over the applying roll. In the manufacv ture of blanks from which boxes are to be made, for example, it is desirable to apply a very thin coating of adhesive to the materials to be made into box blanks and, accordingly, the rolls are maintained very close to one another. Pressure is applied to the opposite ends of the rolls to press the adjacent ends close together to produce coating of the desired thickness. The axes of the rolls are usually maintained parallel to one another but with this arrangement there is a tendency for the rolls to bend slightly under the influence of this end pressure. The result of this is that the pressure decreases toward the central portions of the rolls. This bending or bowing of the rolls may be due to a bending of the shaftsgm, which the rolls are mounted and also, if either of the rolls has a peripheral surface of a material such as hard rubber, by the flexibility of this surface. The result of the unequal pressure between the rolls is to cause the transfer of a film of coating material of greater thickness to the central portion of the applying roll than to the ends thereof so that the film of coating material deposited upon the work is not of uniform thickness. While this variation in thickness may be very small, and of the order of a very few thousandths of an inch, the variation is material if the thickness of the coating material is to be only'a few thousandths of an inch, as is customary in the application of adhesives to materials used in-making box blanks.

One of the features of the present invention is the arrangement of the rolls so that the pressure between the rolls is uniform throughout the lengths thereof whereby a uniform thickness of coating may be transferred to the material being coated. In order to produce this result, the axes of the rolls are skewed slightly relatively to one another to produce a slight wrapping of the rolls around one another so that the same pressure is exerted between the rolls at all points along the contiguous surfaces thereof. The more the rolls are skewed relatively to one another, the greater is the pressure between the rolls at their mid points relative to that at the ends thereof, and by properly adjusting the relative skewing of the rolls, a uniform pressure along the entire length of the rolls may be obtained to cause a uniform thickness of coating material to be applied to the work.

Another feature of the invention is the provision of means by which either end of one of the rolls may be selectively adjusted with respect to the other roll and, if desired, both ends of one of the rolls may be simultaneously adjusted with respect to the other. To this end, provision is made for connecting the adjusting means for each end of the roll so that they will be operated as a unit when it is desired to adjust both ends of the roll simultaneously.

. These and other features of the present invention will now be more particularly described by reference to the accompanying drawings and pointed out in the appended claims.

In the drawings: I

Fig. 1 is a front elevation, certain parts being broken away and other parts shown in section, of a portion of one form of machine embodying the principles of the present invention;

Fig. 2 is a left elevation of the mechanism illustrated in Fig. 1;

Fig. 3 is a right elevation of the mechanism illustrated in Fig. 1;

Fig. 4 is a sectional view of one of the eccentric bearings supporting the coating supplying roll;

Fig. 5 is aview illustrating diagrammatically the distribution of pressure betweenthe two rolls .when the axes are parallel to one another;

Fig. 6 is a view similar to Fig. 5 but showing the rolls with the axes thereof skewed slightly to one another; and v Fig. 7 is a view similar to Fig. 6 but with the axes of the rolls skewed excessively with respect to each other.

The coating-applying roll it is mounted on a shaft I! supported in bearings l4 and Ii (Figs. 2 and 3) mountedon the fixed arms I8 and 2|,

respectively, which extend substantially parallel to one another and which form part of the frame work of the machine. The applying roll II is formed of any suitable material such as hard rubber and is arranged to receive coating material from a supply or pickup roll 22, a portion of which rotates in a receptacle (not shown) containing the coating material. The supply roll has a relatively hard surface compared to that of the roll I8 and may be made of steel or bronze. The roll I8 transfers the coating material from the roll 22 to the Work to be coated which passes over the roll I8.

The roll 22 is mounted on a shaft 24 which is supported at its ends by means of eccentric bearings 26 one of which is illustrated in section in Fig. 4, these hearings being in turn supported by the U-shaped frames 28 and 38. These frames are swingably supported by means of sleeves 32, 34 (Fig. 1) which pass through the arms I8 and 28 rearwardly of the roll supporting shaft I2 and thesesleeves form bearing surfaces for a shaft 36, thefunction of which will appear as the description proceeds. The U -shaped frames 28 and 38 en a e the opposite walls of the arms I8 and 28, as indicated in Fig. 1, so that these frames are prevented from moving lengthwise with respect to the rolls I8 and 22. Collars 38 and 39.

fixed to the shaft 36 engage the frames 28 and 38 to prevent axial movement of the shaft.

The U-shaped frames 28 and 38 are urged in a clockwise direction, as viewed in Fig. 3, about the shaft 36 by means of springs 48 engaging members 42 secured to a shaft 44 passing through the rear portions of the arms of the U-shaped frames 28 and 38, so as to press the coating supplying roll 22 against the transfer roll I8. The

members 42 form enlarged end portions of rods the arms of the U-shaped frame members 28 and 38, as indicated in Fig. 1. The inner ends of the abutments Y48 and 58 engage shoulders 54 (Figs.

2and 3) of the frames 28 and 38. The forward ends of the adjustable abutments'48 and 58 are formed as reduced shank portions 56 and 58 and are journaled in U-shaped housings 68 and BI, respectively, which are fixed to the arms l8 and 28 and extend downwardly therefrom. The reduced portion 58 of the adjustable abutment 58 has keyed thereto within the housing 6| a worm gear 62 which engages a worm 64 mounted on a shaft 66' journaled in the upper portionsof the gear housings 68 and 6|. The shank portion 56 of the movable abutment 48 carries a worm gear I8 in the housing 68 and this worm gear engages a worm I2 mounted on a sleeve I4 journaled on the left end of the shaft 66 and in one of the arms of the gear housing 68. right end of the sleeve I4 is formed with anflnnular groove which receives the reduced end of a screw I6 to prevent axial movement of the sleeve. Upon rotation of the sleeve ,14 and the shaft 66 as a unit, the worms carried thereby rotate the worm gears '62 and 18 to cause simultaneous rotation of the abutments 58 and 48 which will in turn move axially since they are threaded in the depending portions 52 of the arms I8 and 28. These abutments move in the same direction so as to move the roll 22 away from the roll III or permit movement of'the roll 22 toward the roll I8 under the force of the springs 48, depending upon the directions of rotation of the sleeve I4 and shaft 66. Thus, when the sleeve and shaft are rotated simultaneously both ends of the roll 22 are adjusted with respect to the roll 18.

It may some time be desirable to adjust one end of the roll 22 with respect to the roll I8 without similarly adjusting the other end of the roll and, accordingly, provision is made for imparting independent rotation-to these members. A knob I8 is keyed to the outer end of the sleeve I4 and a second knob 88 is pinned tothe outer end of the shaft 66 which extends outwardly with respect to the sleeve 14. The knob 18 is provided with a cylindrical extension 82 which fits within a cylindrical extension 84 of the knob 88. A screw 86 passes through the cylindrical extension 84 of the knob 88 and the inner end of the screw is reduced and is received in an annular groove in the extension 82 of the knob I8 to prevent relative axial movement of the two knobs. A pin 98 is slidably mounted in a hole in the knob 88, the length of the pin being slightly greater than the thickness of the knob 88. The extreme left end of the shaft 66 is threaded to receive a nut 92 which forces the right end of the pin 98 into engagement with the adjacent surface of the knob 18 when the nut 92 is tightened on the shaft 66; When the nut is thus tightened, sufficient pressure is exerted by the pin 98 on the knob I8 so that the knobs may not be rotated relative to one another whereupon rotation of either knob ,will cause the shaft 66 and the sleeve I4 to rotate simultaneously. If, however, the nut 92 is loosened so as to relieve the pressure between the pin 98 and the knob I8 either knob may be rotated relative to the other so that either the sleeve I4 or the shaft 66 may be individually rotated to adjust either end of the shaft 24 carrying the roll 22 relative'to the other end to vary selectively the pressure between the two rolls at each end thereof, if desired, in

order that a coating of varying thickness may be supplied to the roll I8. A pointer 96 carried by the sleeve 14 co-operates with suitable therein. One of the surfaces inthe frames 28 and 38 may be formed upon an insert I82 to facilitate manufacture thereof. outwardly of the bearing surfaces I88, the bearing 26 is substantially cylindrical and these surfaces are spaced from the adjacent surfaces of the U-shaped frame members to permit limited rocking movement of the bearing about an axis extending transversely therethrough. understood'that the bearings at both ends of the roll supporting shaft 24 are similarly formed v be skewed with respect to the roll I8.

In order to enable this simultaneous rotation of the bearings 26 in opposite directions to effect this skewing of the rolls, arms I84 and I86 It will beare connected rigidly to the external surfaces of the bearings, as by screws I06, these arms extending outwardly with respect to the roll 22. The arm I04 connected to the bearing at the left end of the shaft 24 has a portion extending substantially concentric with respect to the roll 22 and teeth IIII are formed on the inner side of the extended portion of the arm, as indicated in Fig. 2. The teeth IIO engage a gear II2 carried by a sleeve II4 (Fig. 1) journaled on the shaft 36. The arm I06 connected to the bearing at the right end of the shaft 24 is also provided with a portion extending substantially concentric to the roll 22 and having teeth II8 (Fig. 3) on the outer side thereof engaging a gear I20 carried by the shaft 36. If the shaft 36 and the sleeve H4 are rotated as a unit, the gears H2 and I will be rotated inthe same direction and the rotation of these gears will be imparted to the arms I04 and I06 connected to the eccentric bearings 26. Since the teeth on the outer ends of the arms I04, I06 are oppositely disposed with respect to the gears II2 and I20, respectively, rotation of these gears in the same direction will cause the arms and the eccentric hearings to which they are connected to be rotated in opposite directions. In order to cause simultaneous rotation of theshaft 36 and sleeve II4, a knob assembly I24 may be employed, this knob assembly being similar in construction to the knob assembly, including the knobs l8 and 80, for moving the large roll toward and away from the small roll I0. The nut I26 of the assembly I24 will normally be maintained tight against the knob connected to the shaft 36 so that the two knobs will rotate as a unit, but if occasion should arise, the knob I26 may be. loosened to permit independent rotation of the shaft 36 and the sleeve H4 and individual adjustment of the eccentric bearings. Thspherical outer surfaces of the bearings 26 permit rocking of the bearings with the skewing of the shaft 24, so that the axes of the bearings may remain in alinement at all times.

The outer end of the arm I04 carries a pin I26 (Fig. 2) adapted to engage the gear II2 upon movement of the arm I04 in a counterclockwise direction, and this pin co-operates with the. portion of the arm I04 which extends substantially radially from the bearing 26 to limit movement of the arm I04 by the gear II2 which, in turn, limits the rotational movement of the bearing 26. Pins I30 and I32 (Fig. 3) in the arm I06 similarly limit rotational movement of this arm and the bearing to which it is fixed, these pins engaging the gear I20 upon sufficient movement of the arm in one direction or the other.

In order to prevent unintentional rotation of the shaft 36, a disk I36 having a serrated edge is fixed to the shaft 36. A latch I38 is pivoted on a pin I40 mounted in the outer wall of the U-shaped frame 28 and a spring I42 connected to the pin and the latch urges the latch into engagement with the serrated edge of the disk I36. The part of the member I30 which engages the edge of the disk I36 is also serrated so that the latch I38 must be retracted against the tension of the spring I42 to permit rotation of the shaft 36, the latch having a finger piece I48 (Fig. 2)

to permit of such retraction. An indicating line I50 cut into the surface of the latch I38 co-operates with indicia on the surface of the disk I36 to indicate the degree to which the rolls are skewed relatively to one another.

Figure 5 is a diagrammatic view indicating the pressure between the two rolls whenthe axes are parallel. When pressure is applied to the rolls at the ends thereof to force the rolls together, as by means of the springs 40, there will be a tendency for the rolls to bow at their central portions so that the pressure between the rolls is somewhat greater at the ends thereof than at the central portion, as indicated by the shaded area bounded by the broken lines. This bowing of the rolls (or one of them) upon application of pressure to the ends thereof is caused by reason of the resiliency of the roll shafts and also by reason of the resilient surface of the applying roll I0 which may be formed, as previously stated, of hard rubber. This tendency of the rolls to bow may be very small and of the order of only a few thousandths of an inch but the result of this tendency is for a thicker film of coating substance to be transferred from the supplying roll to the applying roll so that the material being coated will have a somewhat thicker him at the center than at the ends thereof. In many types of work, such as the making of box blanks and the like, thefilm of glue applied to the materials making up the blanks is generally a very thin layer of the order of a few thousandths of an inch and should be uniform in thickness to secure the best results. Accordingly, this tendency of the rolls or of the applying roll to bow slightly may have an appreciable effect on the thickness of the coating material when applied to the work, particularly when this film is to be only a few thousandths of an inch thick.

If the large roll is skewed slightly relative to the applying roll it will tend to conform to and bear uniformly upon the applying roll thus causing a more uniform pressure between the rolls. The axes of the rolls may be skewed just sufficiently, as indicated diagrammatically in Fig. 6,

so that the pressure throughout the lengths of the rolls is uniform, and when properly skewed to create this condition the thickness of film of the coating material supplied to the applying roll will be uniform so that a film of uniform thickness will be supplied to the material being coated. Fig. 7 indicates diagrammatically the pressure between the rolls when the rolls are skewed excessively so that the applying roll tends to wrap around the transfer roll to a greater extent than is desirable. At this time the pressure at the ends of the rolls is considerably less than at the central portions thereof and if the rolls were utilized in this conditionthe thickness of film applied to the work would be greater at the ends than at the central portions. The desirable condition of the rolls to obtain a film of uniform thickness is obtained by simultaneous rotation of the shaft.36 and sleeve. I I4 which imparts rotation of the eccentric bearings 26 in opposite directions to swing the roll 22 about an axis passing transversely through the roll and perpendicular to the axis of the roll I0, and when the proper adjustment of the roll has been made, the pressure between the rolls will be uniform throughout the lengths thereof as indicated diagrammatically in Fig. 6.

Gears I50 and I52 on the right ends of the shafts I2 and 24 respectively cause simultaneous Y rotation of the rolls I0 and 22 in opposite direcpart a higher peripheral speed to the roll I0 than to the roll 22. The rotation of the roll I0 at the higher peripheral speed insures that an excessive with respect to the other of said rolls while maintaining equal pressures at the opposite ends of said rolls. a

2. A coating mechanism comprising a pair of co-operating rolls, eccentric bearings supporting 'the ends of one of said rolls. and unitary means for simultaneously rotating said bearings in. op-

posite directions. v

3;. A coating mechanism comprising a coatingsupplying roll, an applying roll receiving coating substance from the supplying roll, eccentric v one of said rolls for causing adjustment or the bearings supporting the ends of one of said rolls,

an arm rigidly connected to each or said eccentric bearings, said arm having ofiset portions extending substantially concentrically with respect to said one oisaid rolls, external gear teeth on the outer surface of the oflset'portioii or one of said arms, internal gear teeth on the offset portion 'of the other of said arms, gears engagporting said one of said rolls are rotated in upposite directions.

LA. coating mechanism comprising a. coatinganswer last-named means ineflective to rotate simulta neously said bearings, whereby either 0! said bearings may be individually rotated.

6. A coating mechanism comprising a coating substance from hte supplying roll, a rotatable sleeve, means connecting said sleeve to one end of one 01 said rolls to cause adjustment 01' said 7 end of said roll relative to said other roll upon rotation of said sleeve, a shaitin said sleeve and operatively connected to the other .end of said other end thereof with respect to the other roll uponrotation of said shaft, means. for individually rotating said shaft and said sleeve, and means rendering said last-named means ineflective to cause individual rotation of said shaft and said sleeve while permiting simultaneous rotation thereof.

supplying roll, an applying roll receiving coating substance from the supplying roll, eccentric bearings supporting the ends of one of said rolls, means rotatably supporting said eccentric bear- I ings, the surfaces between each of said bearings and its supporting means being formed :as see- 40 ments of a sphere, and unitary means for simultaneously-rotating said eccentric bearings: in opposite directions.

5. A coating mechanism comprising a coatingsubstance from the supplying roll, eccentric bearings supporting the ends of one of said rolls, means for simultaneously rotating said l s in opposite directions, and means rendering sai 8. A coating mechanism comprising a coatingsupplying roll, an applying roll receiving coating substance from the supplying roll, unitary mechanical means for simultaneously adjusting the ends of one of said rolls about a transverse axis extending substantially through the center of said roll, said axis being perpendicular to the axis of the other oi said rolls, and means for indicating the angularity between the axes orsaid rolls.

9., A coating mechanism comprising a coatingsupplying roll, an applying roll receiving coating substance from the supplying roll, unitary mechanical means for simultaneously adjusting the ends of one of said rolls oppositely with re- A spect to the other-of said rolls while maintainsupplying roll, an applying roll receiving coatin respect to the other oi sai rolls.

I i D. KNOWLTON= 

